Machine for cutting noncircular gears, cams, and the like



Nov. 4, 1952 .1. G. TAPPERT ET AL 2,615,337

MACHINE FOR CUTTING NONCIRCULAR GEARS, CAMS, AND THE LIKE Filed March 30, 1948 4 Sheets-Sheet l QMNII 2.8mm

l om OO- $338930 NI 80M d0 NOIJNLOB own Nov. 4, 1952 J. G. TAPPERT ET AL MACHINE FOR CUTTING NONCIRCULAR GEARS, CAMS, AND THE LIKE 4 Sheets-Sheet 2 Filed March 30, 1948 Nov. 4, 1952 J. G. TAPPERT ErAL 2,615,337

NONCIRCULAR GEARS, C'AMS, AND THE LIKE MACHINE FOR CUTTING 4 Sheets-Sheet 5 Filed March 30. 1948 TTmFeNE/- Nov. 4, 1952 J. G. TAPPERT ET AL MACHINE FOR CUTTING NONCIRCULAR GEARS, CAMS, AND THE L/IKE 4 Sheets-Sheet 4 Filed March 30, 1948 T. m a m E N P VL P W. MH

d IIE Patented Nov. 4, 1952 MAQHINEy FOR CUTTING NONCIRCULAR- GEMS. QAMSMND THE LIKE...

J ohnaG. Tappert and William.Spe1-ling,. Philadelphia, Pa.:

Application March 3;0 1948, Seria1` .Np..1r.8,r 04"7 10 .Glaims....(Cl. 90-7) royalty: thereon.

Thisinyentionrelates to a machine I.foiscritting non-emular gears.; cams andltheflikeif- Itis en obieetef this inventioato .rrorde s machina-Consisting,-of .a standard eeav Shaper modified; ,te permit a-Speed ,of rotation o f vthe .work

table which may be continually vari-edin accgrdance with a predetermined.patternLand alsgalv 10W.11 1e ier distance .betweenithe oenter of thecutter. and; the center of thefwork .tahle which j may he v continually g varied .in accordance with a predetermined pattern.

It iS. e.. further Aoloieet .of this .invention to yprovide a machinein lwhich the..continually-varied' speedof rotation .of theworl;.tableandftho con,... tinualiy-yarieddistance between Itheycenter. .of the;

cutter and the center vof thework table are.. con trolledspy l rnechanismsv which operateI at a, larg.. scale. gfactor.` f advantagaf thus reducing the", ac

curacy requirements l of Ithe :ontrollingY machine parte,

It Aisfyetanother, object of thisinVention-to prof. L..

videl a machine which is capablefof attaining-ther foregoing., objects but Awhichnevltthelessjs, cap.able .of usevas astandard gearshaper vfor producing..

Circular gears In general, therefore, an.- object- Aof thisf innen.

tion .is to provide a machinejon producing v`non-fcircuA rninechan-ical eleinents, -such as gears;,or,f.., cams,y .a simple, economica;1,..and. expeditious manner directly from `the computed drafts. -Em

ployxnentiot thi'sr-mahineWillmake `it possible; .to circular-gears without the. necessity.A

produce Ii of gv eitherapproximations or the repro-...

the past., In additrion,l employment .of

, al Wilifmale it pos/sibievdirectlyf-to generata-.cams of any, ,sha-pe with .la continuous.

surf'ace'dthat/.yyiliveliminatepthe necessity.` of either filing-...thelsur'face betweenthe nitenumher of poin-VA o ther productionlof ama-ster element as .1

Sueh, a machine may operate. either,completelyautomatically or under.: ther.

Leontrol ,of one .vor more operators.

.arefiavailahle which will. .duplicate` SPQIIlaChII-Ralts.having non-circu-- lar Eoutline/sl.n I. viioyvever, sjuch machines not. only..

reproduce.anyy inaccuracies in the macline part. `selected as a master, but-aisointroduce Afurther inaccuracies inevitably.r resulting from the *repro-.

ducngf inachine itself. Moreover, s0me;1.eproducing y. machines have, seriousl limitationsl von t he. ;.k curvatures. of the rnac'hine parts which may.. be

feereeueesiflf Otherobieets- Off .this invention. and ai further. andfullerdescription.of some. em'bodiments-thereof maybe hadby referenceto theannexed .drawings andrspeciiication. at thev .end whereof :thef noretfeaturescf 1theinvention will ber-.explicitly pointed .outand claimed...

In thedrawings.:1:.;4

Figa; is a, chartlor ,graphuseful in describingthe invention Fig: '-2 S;a -diagram1 in block, forn1 schematically showing Lour-..irwentiye .modification of a standard s. circulareearshaper which .enables it to be used for lcuttingnonfcircular; gears, cams, etc...;.` Y

Figfa is a..b1ock.,.diagrarn.showing in schematic. form.. the .parts f :of ...the ....Fig. 2 machine when o equipped.v 4with a. manual type .computing .-mecha-v nism; and

Figs. AA. `.and A1B Aare. the two halves.. ofasche-z f.. matic .or diagrammatic representation of our. in. ventive machine-When A.providedoivitl'x-- the manual typetcomputereas shownin Fig. 1.

Thereexists at .presentJ a demand for non-,-cir..-... cular. machine parts-such as gea-rs-and the /1ike. Onemethodby x.which .the proper shape A`of the gear, pitch line'has-.beengenerated in the pastre-f quired -laborious `calculations which l involve a-p-v prox-mations vand,"estimates-so that the 'fin-a1 re; V sult-isnot rigorously-exact. As a result ,of em"-v ploying-thisj -meti 1od, gpairs of Ygears have-high A pointsv and low 'pointst on the meshing teeth there 0f and. eenseaueetlyfaust .be lapsed teeetherte" A provide .Smooth .runnin In iadditieaexistne. means et manafaeturne. eamsreouirethet 'a masterelment .be out yby a method of spotting .a Iinite. number lof-points aroundpthe .cam .surfaceandiing the interven ing ledges, untiiga cgntinuoussurface is obtained l This ,method of manufacture,requires laboriousfl ling and,A unless, egitreme VY'precautions are, exer cised.resu1 ts in a. piece that is.. only. approximately correct.- Mass production of the required cams is, theaaooomplisheahy reproduetionzof. the. elementwhich in itself Iintroducesflinthenerrors l that inevitably result .from -f the; reproduoine Process-ff Whenv :generating none-circulan gea-frs; l or any. other toothed non circu1ar;e1ement,.it is neces. sary; to quaiifyat everyinstant .the relationship betweenfthe -rotationof the cutterand the.rota tion of thewworiepiece. .In addition, .the center.- to-center distance ...between the. :cutter .and .the Work pie-ce must. also be qualied with respect-to the rotationof -the..work..piece...When.cutting. l smooth surfaced. .nonfcircular elements such vas camsit isnecessary. to qualify therotation of the Work .,piecewith respect...to the centerto-.center distance between thework and the cutter; 4but it.

is not necessary to qualify the rotation of the work piece with respect to the cutter. Thus, the generation of cams is a simpler process than the generation of non-circular gears and will be dealt with below as a special case under Method of Operation.

For use with the machine of this invention variations of the rotation of the non-circular gear being generated, and also the distance between the center of the gear and the center of the cutter maybe computed at a number of points on the gear. These functions may then be plotted as a function of rotation of the cutter which is rotating at essentially a constant speed. Fig. 1 shows such a curve or graph for one type of gear. The curve A represents ythe rotation of the Work table carrying the work piece being cut, this rotation being plotted as a function of the cu-tter angle. Curve A can be secured as the resultant of the straight line component B (which can be supplied directly from a constant speed motor), and a non-linear component C which is supplied by first computing mechanism 22D (as shown in Fig. 2). 'I'his arrangement results in a smaller excursion of the non-linear function than would be required if the entire curve A were obtained from the computing mechanism. This permits a high scale factor which results in greater accuracy. While the curves shown on Fig. 1 illustrate the typical relationship between table rotation and cutter rotation for one particular ytype of gear ther7 are fairly representative of the relationships that exist for the generation of all noncircular gears.

For many non-circular gears there exists a relationship between the distance between the center of the work rotation and the center of the cutter rotation that, if plotted against cutter rotation, gives a non-linear curve that is either predominantly increasing or decreasing (depending on the direction of cut). When this is true the function resembles that plotted as curve A in Fig. 1 and may be broken down into a straight line and a non-linear function as Was the table rotation relationship. In this cfase the non-linear component is supplied by second computing mechanism 236 (as shown in Fig. 2) with an increase in accuracy as was realized for the table rotation. It should be noted, however, that when the generated gear is ire-entrant (i. e. with teeth around the entire gear so that the gear can operate any number of turns) the cutter will end the cut at the same position that the cut was started. In this case the motion is nei-ther predominantly increasing o1- decreasing, which mean-s that the linear component is zero and that the entire movement is non-linear `and must be computed by second computing mechanism 235.

Fig. 2 schematically shows a conventional circular gear shaping machine as modified by our invention for cutting non-circular gears. This machine consists of the main or primary motor I Which, by means of connection 4, drives the first computing mechanism 228. Mot-or I, through connection 3, also drives cutter rotation and reciprocation mechanism 2 so. that the cutter rotation is proportional to the rotation of the main mot-or, which is operating at essentially constant speed. As the input of rst computing mechanism 220 is also proportional to the rotation of motor I, the input rotation of this mechanism is directly proportional to the rotation of the cutter. First computing mechanism 22D is designed so that with an input rotation proportional to the rotation of the cutter the output` rotation is proportional to the non-linear component of ytable rotation as represented by curve C in Fig. l. As the internal mechanism of first computing mechanism 220 is of necessity high grade instrumentation, it is not capa-- ble of exerting sufficient torque to operate the heavy machine parts of the gear Shaper. For this reason the output torque of the computing mechanism must be amplified by rst torque amplifier 9. The output of torque amplifier 9 is fed back to the input side of mechanism 22E. In addition the output of torque amplifier 9 is fed to one gear of the second differential I0, the other'input of which is directly driven from motor Ik by a part df linkage d and whose rotation is therefore directly proportional to rotation of the cutter. By :a proper selec-tion of gear ratios throughout the mechanism this rotation may be made to represent the linear component of table rotation as shown lon curve B of Fig. 1. The algebraic sum of the inputs to secon-d differential I0 is therefore, -at every instant, proportional to the correct table rota-tion that is required for generating the gear as shown on curve A of Fig. 1, and is fed th-rough the change speed gears Il and through suitable rotating mechanism to work table I2.

Motor I drives, by means of connection I3, a second computing mechanism 230. The function of this computing mechanism is quite similar to the function of first computing mechanism 220 in that the input rotation is directly proportional to cutter rotation and the output rotation is the specified non-linear rotation that is required for generating a particular gear. While first computing mechanism 220 provides the table rotation function, the output of second computing mechanism 23B controls the center-to-center distance between the cutter and the work piece. In the case of a gear in which this function is predominantly increasing or decreasingy and therefore contains a straight line component, the addition of the linear and non-linear components is made inside of the computing mechanism. The output of second computing mechanism 23! is therefore proportional to the total instantaneous centerto-center distance between the work and the cutter. The output torque of second computing mechanism 23B must be amplified and is fed into second torque amplifier I 8. The output of torque amplifier IB is fed back to the second computing mechanism 230. In addition the output of second torque amplifier I8 is fed through a gear shift 290 to a nut I 31 (see Fig. 4A) which when rotated on differential lead screw ZI changes the center-to-center distance between the work and the cutter. Depth of cut servo motor 22 is also connected to differential lead screw ZI. It is connected in such a manner that operation of the shervo will cause the lead screw to translate, thus changing the center-to-center distance between the cutter and the Work even though second torque amplifier I8 is inoperative. Servo motor 22 is controlled by first computing mechanism 220. At the end of a rough cut on the work, computing mechanism 220 will control servo motor 22 in such a manner that the cutter will be moved in towards the depth of the nnish cut. Because of the geometry of the problem, this movement will influence the relationship between the rotation of the cutter and the rotation of the Work. Consequently the output of servo 22 must be fed back into rst computing mechanism 22E.

The table rotation and center-to-center disline function. When this condition is encountered the entire non-linear function must be plotted on second indicator drum I6 with a resultant loss of scale factor advantage.

Figs. 4A and 4B show in greater detail the parts yof the machine when set up for manual operation. (This is the same condition that is shown on Fig. 3 in block diagram form.) The mechanism shown inside the dotted lines, generally indicated by 220 and 238 are the removable computers. In the illustrations, manual computers are shown. All mechanisms outside the dotted lines are permanent parts of the machine and are used with any computing mechanisms. Fig. 4B shows a table rotation drive. Under manual operation the depth of cut servo 22 is not used as the operation is not automatic. The operation of the table rotation drive is described below.

Primary or main motor drives, by means of a shaft 3 and a second shaft 25, which is a part of the gear train generally indicated at 4, a spider 26 forming a part of second differential generally indicated at lo. The spider 25 is part of the input to differential lo. Shaft 25 also drives a chain of spur and bevel gears (generally indicated at 21) connected to a shaft 28 and a coupling 29, and a second chain of gears generally indicated at 33 which lead to an elongated gear 3|, meshing with a gear 32 having a screw threaded nut BIB mounted integrally therewith. Gear 32 is connected to first indicator drum 1 on which a chart bearing curve D may be mounted. While the Work is being cut the first indicator drum 1 will be driven by the gears 3 32 at a speed of rotation directly proportional to the speed of rotation of the cutter 25|). (Vlhile the primary purpose of this drive is to rotate thel drum, a slight translation will be caused by the mechanical arrangement of having the nut 3|e integral with the rotating drum. This must be compensated for when the curve is being plotted.) As the drum is being rotated at a speed proportional to the cutter, the cutter rotation axis of curve C shown on Fig. 1 is plotted around the circumference of the drum. As the work progresses the drum rotates at essentially a constant speed. The operator observing the chart D through the fixed reticle 33 will see the curve appear to leave the center of the reticle cross hairs. To make the curve return to the center of the reticle, the operator must translate the drum, which is accomplished by turning first handle 3 mounted on shaft 53. Shaft 53 is connected (by means of gears 54, slip clutch 55 and gears 53) with shaft 46 and pinion 45 thereon. A stop 41 limits the rotation of shaft 48 to two revolutions thereby protecting first variable speed mechanism from injury that might result from excessive motion. An adjustment knob 48 and gearing for a dial 49 (for showing the output speed of variable speed mechanism 5) are connected to shaft 46. The variable speed mechanism 5 has a pair of balls 43 connected by means of rack 44, so as to be adjustable from one rim of the input disk 42 through its center of rotation to the opposite rim. Pinion 45 meshes with rack 44 so that the operator, by turning first handle G may move the balls radially along the face of disk 42 from one extreme limit to the other. Disk 42 is connected through spur gears 4|, shaft 43, bevel gears 39, coupling 29, shaft 28, gearing 21, and shaft 25 to motor I. The input disk 42 therefore rotates at what is essentially a constant speed. By moving the balls 43 across the face of the indirect control of both the speed and position of the output of first differential 8 (and therefore the speed and position of first indicator drum 1), permits easier matching of the plotted curve D by the reticle 33` This rotation is fed through coupling |51 to self-synchronous torque limiting device 58. This self-synchronous torque limiting device 53, along with self-synchronous torque limiting devices 35, |96 and |23, operates so as to slip if the torque on the driven member exceeds a certain specified amount. If the torque is excessive for only a short period, that is,4 if the driving member has made only a fraction of a turn, the torque limiting device will return to synchronism after the torque has returned to normal. The output of the torque limiting device 33 feeds directly into the input of torque ampliner e. The power input to torque amplifier 9 is driven by power motor 38. The output of the torque amplifier feeds through gears to coupling 31, a set of gears 35, self-synchronous torque limiting device 35, to lead screw 34 on which is mounted the internal nut 3| which is integral with drum 1. Thus, as the lead screw 34 rotates, the drum will translate the curve D under the reticle 33. This translation is essentially the nonlinear component of the work table rotation represented by curve C of Fig. 1.

In addition to feeding back into the computer, the output of torque amplifier 9 is fed through shaft 59 to bevel gears 60. The output bevel gear 60 has, on its upper surface, a diametral bar 6| adapted for cooperation with a confronting notch 62 in a gear shift member 63, which is operated by means of a handle 64 pivoted at 65. Gear shift 33 has connected to it a pinion 66 meshing with a pinion 61 and having on its upper surface a diametral bar 68 arranged for movement into and out of a confronting notch 69 in a stationary stop 10. These parts form a lock L which is required when cams and circular gears are being cut and first computing mechanism 226 is not connected to the gear train for rotating the work W. If this lock were not provided movement of the input spider 25 of second differential l0 would feed out through input gear 1| instead of through the output gear train that rotates the work. Pinion 61 meshes with a part of input gear 1| which forms a portion of differential I0 of which the spider 26 forms another input part. Gear 12 of differential lo is the output portion of this differential and is connected through the change speed gearing (generally indicated at Il) to a worm gear 13 which meshes with a worm wheel 14 connected to the work table |2 on which the work piece W to be cut is mounted.

Fig. 4A shows the drive for controlling the center-to-center distance between the work and the cutter. Motor drives mechanism 2 (not illustrated in detail) which serves both to rotate cutter 253 in a horizontal plane, and at the same time to reciprocate it vertically so that cutter 250 makes a vertical cutting stroke and a return gnomes? 9 t lIl.slzrokeand vthus .generates'iteeth byscuttingfaway .-ayportion of thel edge of Athefvtorh piece W.

@Shaft 15,connects at its tendiwith coupling 16, 1:..fthe opposite side of: which vis-fconnected toshat 11 which drives bevelgears. 18, A.shaft-.t 1.abevel .,gears..80,.and .spurgears 8Ii,\...conneeted. to an i. elongated. gear 82; which; yrnesl'les-pwitli caifgear: 83 .having Aa.screwthreaded .nuteBZ-.Il mountedin- ,.tegral-ly..ther.ewth..i v.Second.indicator..drum L6 is connectedrtoggear. 83. A chart bearingacuri'e'DD. .whichrepresentsathe nonflinearicomponent in l .thedistance betweenthecenter ofuthemork piece W. .and .the .center of..the .cutteler;25..-.rnay.-. be .-..mounted. on drum I6.

4Motor :aI drives., byf. means oi :.'shaf-t. 15.; ,coupling. .16,..shaft 111, .bevelf-gears 1.8,...shaft- 19,,fand;..s;pur ...gears 8 4,..the.;input disk 85 oifthetsecond variable :.speedmechanismngenerally, indicated at II|i1 The ,-1., .-meehanisrni I 4.; has. an intermediate @member .oif ofydiske.; .Shaft 9...has anadiustmentyhan- Yedle 32 on. oneend of. it.-.and .isieeered by .Worm 93 f..- to=.a .diei l-whieh ieateoitheaoutput sneed of eohanism. I4.

.ILr'lhrd .......difterentiei .Iliservesifthefeem `fiouiuioee. e.s...-.ioo s firot difiotential .8. :that i. oreeseezfthofaoou-a anifollowtbozourve lntial I1 lie .oonneoteot by.-meens oi' ooupiing---l05 and.tneselifsynebronous;teigne iimitine--deyioe 1....:106 .with the. inout to Seoond-.toeiie-.emoliee .83 having en iedditionel .Source .oftpoweresuoh 2te-the' y.; motor LI01-,-. Theoutput ofitorque. amplier I3 is vfed,.throughagioetiir of gearsi @coupling-109, ,5 l. and., a pair ospur .gears'lfl III fto.. an ginputigear I I oi. Whe fourtbfdifierentiei .eenerallyiindicated at w. 2.0,.;.the otherfinput.,par. t o-f which .is..,the,spider f E,.IIZ. V`Tice.,spider.,.| I2if .dr..ven rornzshaft .L1 .by ...ff-means oa pair off-.snurgearsd I3. endo-.I tiene e L...shaft '.II BQ connected tn thasaid spideril I2 ,n 5.The ,l :output .gear ',.I L3 of. @the differential.. generally. .indieeten at 2.0 is -oobneotel Wiener-geared 2li-shaft ,I 2 tenor .gears I 2.2 .anda selffsynohtonous torque A. limiting. device. .I 2,3; with.. alead. Screw, I 2A Whose 4 .threadsengagewith.thethreads m1119320 which .i s integral with gear.. 83.

y Although. the....mechanica1..details l.are slightly" different the operation o.,this.gear`. train.is ,iden- 1 ..tical..withthat of ,theutablerotationomputer. The rotation onthe.,drum.,representstheeutter vrotation .axisoila cur-.ve somewhatemilat to. that. onFig. 1..4 .Translation Qthedruni tepre`= Sento the .nonnlineeneomnonent of,.the..eenterto eentoridietenoeivhioh iseunoton of @titten roy1.--tf.i'.t.i.oni;,..By .transletingthe ...dimm-...using second .......hndlel |5, .and .asvs.ociated,.eguiiomentu untilfthe, curveappears to, coincide.withthereticle repre-l y. lsented by` .-I 5u,- .the.operatoncontrols.. the( computer so that the output Vof ,second @Grqilgiamplii .ner .I 8; drives .the @utter tothe-george@ eenter-tooenterudistanoe.

.formed of Aaepaii" of balls. 36mo.unted manage...

meohanismis not/damaged byirunningttheiballs.

. f Shaft 1.1 has slidablyimounted on-.t agearll I3 which is movable by .handle-.Iltout off'meshiwith ....gear IIi on shaft IIE. '.-.Simultaneouslyhandle f-I III :moves aprojectionl I.1` .into engagement lwith 5 a slot I I3. on. shaftisl ioand therehy.locks-shaft .v I I6 againstrota-tion. When` thegearibengi-cut i yis.reentrantqand thus-.theiunction ofithe centert. to-.centendistance between the lWorlrand the-cut# :....-ter..has nolinear component,..spue.gearII5 is 1.0. -thus 'removed from `mesh .with .gear :I I3. .,When .--.1this is .done thetlinear input to differentials 20 -must be locked. This .isaccom-plished by moving projection vI I1-A i-nto engagement-with slot I I8. The output from second torque amplifier I8 is carried. by -shaft- |25 through change speed gears y indicated at k|26 toA gear |21.4 .Gruear- |28 ismov .able b-xtmeens `oiga bivotebly mounted-.handeln l ,intoandout off/engagement l.Withgearf |21 orzgear ,s H30.- When `cutting-g(,:ircular gears the'fdriyeythat is Y continuously- A. `changing the.` center-to-center 4distance hetweenthe .cutter andtheworlfisurnot equired.. and geant-.|30 may be manuallyrotated byv-means of Ahandle I3I"untilfthecorrvectfcenter gato-center distancefffor thev particularly-circular 25 -,gear,beingcut .isf reached.. The amountithatafthe i* operator changesthe .center-torcenter distance may bedetermined by `readingthe graduations onmicrometerfyl 33., 4.Gear 28 isifastened against ..E...31:. otati0.n.0n .shaft-{IEIZwhich,A in..turn,.`drive a. 30...pair of spurtgearsJM and53|h pungear 33,0 is ..wmounted on tubev .|35 .and secure`d..,theretog. by ,v means of an. elongated. 4.key I 3S` so. vthat, as ,the gear is .driven-.the tube `likewise is driven. ,.{Itube has as a part of-it.a;screyv threadedvnut ,|31 35 which engagesiwith thethreads onfdiferential I...leadscrewA 2|.. Asnut, |31 is.attached to.the ...saddle Za-.thatcarries: cutter., ..25I),.rotationvr of tubeI35. v(and.therefore,nut |31,)..w1l`cause.the .i-.Saddle Ztvtandthereforeccutter 250) toiranslate 4'0. andvoutialong .tliellead screw..4 .Dierentiallead screw 2| is,...`also vthreadably attached in| ;.o.,.gear 1 .I39..v ...The mechanism ,is so arranged.,that asgear .|39..r.otates differential leadscrew. 2|.;.tranlslates ...,...carryng' `Vwith itnut.i|3`|...and. therefore, saddle 415. 2a). v`thereby changing. the. center-to-.centerf-distancabetweencutter. 25|),.andA Work W.. 1 Stop ,|y49. i. i; .while .allowinggeelz 'I 39 to 4rotate, prenentsgear LLI 3Q frorn translating. with.. the.-` lead .screw,...thus .ntosorying themeshv.between gear t I 3.9. and i geef 55W' |II t| on` shaftfMI.. A sto'p..30.0 -.proyiledrts fonction 'being to .preserve-.the mesh-:between ,the i two spur gears |34 and 330, desptetheiactthat gear 330 is mounted on tube |35 whichtranslates as the spur gears-rotate. The drivebetweenfgear 5 336 and tube |35 is accomplished by means of elongated .key I 36. e Gear .I 42 is. slidably mounted on ,shaft I IH. .and is ,movable therealong by means ofia-upivgtally mounted .handle .,.I 43... .Gear .'I 4.2 ,may be., rneshed 604.'.Witlrieear. Milano rotatedmenually bmiiendle onmey loe.toothedwithgeertl@ignotiP teted .mechanically by means yof.serynnotor.'2ti .bien ...adjusts themdistance.,between cutter 25Q and.the '.Worl; hetween r4rough... and v,.nishj Wouts.. when woperatingnnder .fullyy `automatic control When .j -operatingwiththe mentalV competen aeehown iniie@ 4A. VSeiuogrnoto'r 22 .not used @meetinst- ..,..-ment.b.etween .cuts is made byhuse pijhandleml. Referringnoxy to.Fig..fiB,. couplings 2g, 31and 70, .I 5.1,. permit A.the...mee'ha-nismo enclosedwith `detted.-lines fand constitutinggtheifmst.

meobatiistrii22|?. and itefeseooetod-hende i, -.-.-11ts.t .indicator ottimi to be :temoveo aeree-unit pletely automatic type specifically designed for generating a particular gear.

Likewise, couplings 16, |09 and |05 (in Fig. 4A) allow the mechanism enclosed within the dotted lines 230 and constituting the second computing mechanism 230, its associated handle I5, and second indicator drum I6 to be removed from the machine as a unit, and to be replaced by another computing mechanism that may be of the completely automatic type whose output varies in accordance with the output of the mechanism designed for controlling the work table rotation.

METHOD OF OPERATION Cutting circular gears as heretofore When it is desired to operate our improved machine to cut circula;` -gears in a manner heretofore known, the operation is as follows. One member of couplings 29, 31, |51, 16, |05 and |09 are pushed back to disengage member mating therewith, thus disconnecting the computing mechanisms from the permanent parts of the machine. Handle |29 is operated so that gear 28 meshes with gear |30 thereby allowing handle |3| to adjust the distance between the center of the work W and the center of the cutter 250. Moving handle |29 so as to mesh spur gear |28 with spur gear |30 will also activate an electrical switch (not shown) that will turn off servo motor |01. Handle |43 is moved so that the spur gear |44 disengages from spur gear |42. This permits the operator to make a ne adjustment on depth of cut between rough and finished cuts on the work by turning handle |45.

Handle 64 is operated about pivot 65 causing notch 62 to leave engagement with diametral bar 6| on bevel gears 60, thus Ibreaking the gear train between the torque amplifier 9 and second differential I0. This movement simultaneously shifts diametral bar 68 into notch 69 in stationary member 10. This engagement locks one input to second differential I0 so that motor I drives shafts 3 and 25, spider 26, differential output gears 12, change speed gears II and worm 13 which rotates'worm wheel 14 connected to table I2 rotating work piece W. In addition, movement of handle 64 activates an electrical switch (not shown) that shuts off torque amplifier motor 38.' From this point on, operation of our improved machine is the same as that of a conventional machine prior to modification by our invention.

Novel method of automatically cutting nortcz'rcalar gears Referring to Fig. 2, the first computing mechanism 220 and second computing mechanism 230 are set in place. It is assumed that the two special computing mechanisms have been` designed, manufactured, and adjusted so that their internal mechanisms are in synchronism and in position for cutting a predetermined portion of the work, such as one end of the gear being cut. The input to first computing mechanism 220 that is driven by the output of depth of cut servo anism is set at the predetermined value. The hand crank indicated as part of gear shift 200 is rotated until the center-to-center distance between the cutter and the work is set at the predetermined amount.

Referring now to Fig. 4A, lever |29 is rotated about the pivot point until spur gear |28 engages with spur gear |21, thus completing the gear train between second torque amplifier I8 and differential lead screw 2|. Moving this lever also activates an electrical circuit so that when power is applied to the main motor I servomotor |01 is also energized. Next, couplings 16, |05 and |09 are engaged. One member of each coupling is adjustable so that the engagement may be made without disturbing the settings of the computing mechanism 230 or the cutter position.

Referring now to Fig. 4B, lever 84 is turned about pivot 65 to shift spur gear 68. This shift causes diametral bar B8 to leave notch 69 and notch 62 to engage diametral bar 5 I. This forms a continuous gear train between first torque amplifier 9 and second differential I0. The movement of lever 64 also activates an electrical circuit so that when power is applied to main motor I servomotor 38 is energized. Next, couplings 29, 31 and |51 are engaged. (In addition, first computing mechanism 220 is coupled to gear shift 23 by a gear train that is not shown on Fig. 4B but is indicated on Fig. 2). One member of each coupling is adjustable so that engagement may be made without disturbing the settings of any mechanism.

The machine is then set into operation. At the start of operation an electrical system (not shown) which is a part of first computing mechanism 220 activates depth of cut servomotor 22 to translate the cutter into position for the rough cut. Starting the machine also energizes main motor I and servomotors 38 and |01.

Motor I rotates shaft 3 and causes the actuation of mechanism 2 which rotates a reciprocating cutter 250 at essentially a constant speed. Motor I also rotates the linkage designated at 4 which causes direct rotation of one input part of second differential I0 and causes rotation of a second input part of second differential I0 through first computing mechanism 220 and first torque amplifier 9. In addition to rotating shaft 3, motor also rotates the connection generally indicated at I3. This causes rotation of the input to second computing mechanism 230 and consequent variable output from second torqueV amplifier I8. This variable output of second torque amplifier I8 is fed through gear shift 200 and differential lead screw 2| to the mechanism I9 which controls the distance between the center of cutter 250 and the center of work piece W. Thus, the distance is caused to vary in accordance with the variation required to cut a gear ofthe desired shape. The output of second torque amplifier I8 is also fed back to an input to second computing mechanism 239 and is used as part of the computation.

Cutting progresses at the depth of the rough cut until the work has made slightly more than one revolution from the point where cutting started. At this point a switch (not shown) in first computing mechanism 220 is automatically closed, again activating depth of cut servomotor 22. The servomotor drives until the cutter is at the correct position for a finished cut. The servomotor is then shut off.

After approximately two turns at finish depth of cut, the machine is shut off by another switch '-(hotl shown):V i'nxiirstncomputing mechanisnr z228. heffcutterz-258 is simultaneouslytranslated: by wthe-fidepth' ofafcut servomotorl 22 to v-the initial position Where it clears the WOrkJ-:xAttheend of1a-cuta bell (not shownyirings to call the atf .extention of the operator toftheiiact thatfthefwork c. is: completed.4 Thefinished part isv removed, a 'anew-1 blank is f put into. position, :andthe cycle is repeated Novel method of'manually c'wtting'non-cicula gears ',.fffspectivelm as shown on-gFig. 3*.'- AWhen changing #nimm-cutting one type otfgear to another, no V.Madditiona'l.- .machine worki' on. the l.computing 'f--:mechanisms is-'requiredY y The manual operation which isfpossible Withour-machine -i-sfdescribed elow.

.,f-Curves D andfDD'are-plotted in accordance With-fthe computed -datafor-thegears to be cut.

'-l. The-curvesarerthen attached to-indicator drumsl -flffiandr lsrespectvely-Hf Certain gears in computingemechanism--238 are changeable- (seeFig. JAA) .v These gears :are spur gears I I3 and I I5 andthefgearslgenerallyindicated at 8-I, 84 and 4221: Thefsame istrue of computingmechanism --fi228-Y shown on- -Fig.. 4B-. InV thisfcomputer vthe ifa-@gears-generally indicated a-t 38, 3-and 81 are changeable.- y After-f placing curves Dy aand .DD on -their respectiveindicator drums,.thecorrect change gears are set into'place. v Thetwo manual typecomputingmechanisms arethenset in pos `vs ition and.l attached toi'the main. .body of .the 'gear-5I I9 of .differential 28. :,:The rotation-eigentput'fgear i I I9: drivesfspuri'gears-fl 28,; 'shaftrIZ I, `spur gears I 22, 'selfesynchronous torque;r limiting machine v:"Settingup tthe machine is carried, on in a mannen similar to -that described for automatic operation except that :for -manual voperation depth of cut servoV 22 'is not-used, -IThe Work table is rotated-fand thecutter is Y. translated manually tothestarting position: levers 64 and I29ware. activated and. the couplings engaged. The spur -gears,igenerally indicated by |22 and meshed for adjustment.'-As;-.there isnnoifautomatic :compensation of table .rrotation fonicoarse cut, `two curves .are 4plotted-.ins-ted o :the-i single curve indicated at D in @Fig 43.12 The .curves -are plotted in contrasting fcolors: Y' For a coarse "cut, the operator `.follows one curve, .Whilezon the finished cut he follows the other, curve. Cutter 258 is brought into-positioniorifthe. start of the coarse out. V"The machine isffthen-fready tobegin the, cutting operationv;.R,eferring now to- Fig.` 4A;-.m0tor I is.-.-then energized.- .This motor therefore rotates-shaft 3..causingrotation of 'cutter 258iandsimulvtaneously. `causing reciprocation. of` cutter $258,

giving it `ay cutting stroke i and Va returnfstroke.

- .MotorI eausesretation of-.shafts -815, ,I'I;bevel gearx 18; shaftg T9,- vspur-:gears: 84,...l and vdriving diskl 85 of-:secondfvariable speedmechanism I4.

The outputv speed of-mechanism Ill;I depends on .thevposition ofy the balls 86 .Withirelation to. the

,- :center of; input disk .85.,y yTheposition ofi: balls 86 in turn depends upon the operation of-,second handle I5. Rotation of handle I5Vturns shaft 95, spur "gears 96,slip cli'itcl'i g1g-'spur gears 88, shaft 98,:spur gears 89 andpinion88.=Rotation oflpinion- 88 movesairack 851 :and-balls 8-8fcon- ,;..trolledthereby-relative tofthe ,centen ofginput .disk 85.... .Constant speedv` rotation ofrinputa disk 85 is.,ftherefore:;.:delivered:, asfanf-outputi-fspeed ser "varyingi under the4 .control of'. handle L5 toaithe :output roller 183, gears-l I82;1` tocinput'geanll 3 of. .thirdfdifferential I 'ILL j; The@v speed of: i rotation of a manually operated shaft 85.is;.-fedv;directly ithrough--bevelgears 98 tontheg-inputzgear |88 chronous safety? device-*I 86` toV `4second` torque pamplienil. ..The.'output of latorquev amplifier fourthldiieriential; 28. Thesspeed of-fmotor I 1. an'dlI I.5. andvshaftcl I5 to rthe-,spiderfl I-2 of: differential:..28. The algebraic.,y sum ofttheiinputs tol'gear I II andi aspider'iI I2. drives,V the output 8I." in Fig. 4A are unmeshed. --Turning .lead

-"curve DD' aligned -wit-hi;the.fcrossqhairs of-Lthe r: screw-128 bywhand translates the indicatordrum .I6,.-and turningpinion 82 rotates the drum. .,-'By-frotating Y-and translating second` indicator V-.:.. -drum IB.-untilthewstartingpoint on curve DD :il l,brought jinto Y coincidence with Ythe reticle I 58, i computingmechanism-238 is brought .into ad- .,ozejustment. The gears' are then re-.meshed-.f (Bewcause ofthefinite'number of teeth on thegears ita-may benecessary to rotate ortranslate the indicator drum I6 one-half tooth fromathe ad- "justed-position, :but this small erroriwill be imperceptible'because of .the `lhighv scale factorsy involved.)

Thefsame-procedure is'vfollowed in adjusting .=frst--computing-mechanisnr 228: shown onvFig. 4B.: In this Vcomputing mechanism spur gears vgenerally :indicated by4 38 -andv 38+may be un,

1'I, bevel gears 'I8,.shaft.19, bevel gears 88, spur gears 8|, and elongated gear 82 meshing with gear 83; i Rotation ofmgearY 83:.causes;drum I8 to' rotate about l'eaizlscrewC |24 as an axisigfiHandle I5 'isf rotated at a suiiicient 4speed to :keep y,the

' reticle'f I 58.

" Aslthework offfcuttingf-thei gear'cprogresses,

chart DD throughwretic1e.. |58. the; curve.. will appear to lleavethe center of .fthe-:- reticleizi To re-'align'the-A chart With-the reticle it becomes "'.necessary tov translate-the drumr to-the-right i or leftias thecase-maybe). `rlhis the operator does by the correctv manipulation of handle I5 and .associated mechanisms; The' output of .second torque amplifier I8 goes from;v shaft I25 Y |32, gearjd and gearL338. This causes' tube 15.4.I35 to rotateliwhich in. turn; rotates"nut"l3`l.

Rotation of nut |31 relative to lead screw 2l causes it to translate along the lead screw carrying with it saddle 2a and therefore cutterA 258. By this means the center-to-oenter distance between the work W and cutter 250 are adjustable in accordance with the function plotted on curve DD.

Operation of rst computing mechanism 22d shown on Fig. 4B is similar to that of second computing mechanism 230 and will not be described in detail. The operator, by manipulating handle 6 and associated mechanisms, translates drum l until the curve plotted on chart D (Fig. 4B) coincides with reticle 33. Thus input movement to first torque amplifier 9 is controlled so as to vary in accordance with curve C, the non-linear component of the table rotation, shown in Fig. l. The output of torque amplier 9 feeds into second differential I0, where it is added to the linear component of table rotation- (curve B of Fig. 1) to give the total rotation function shown on curve A, Fig. 1.

Novel methodrof cutting cams Cams may be generated by either manual or fully automatic means such as described for the generation of non-circular gears. When generating cams it is not necessary to qualify the relationship between the rotation of the work and the rotation of the cutter as is required when cutting non-circular gears. As a result first computing mechanism 220 is not required for the generation of cams.

As the relationship of the center-to-center distance between the work piece and the cutter musty be qualified with respect to the rotation of the cam blank, second computing mechanism 230 is required and its operation, either manual or automatic, is carried on exactly as described for the generation of non-circular gears.

The method of operation for cutting cams is therefore as follows. Computing mechanism 220 is disconnected from the machine by a method previously described. Handle 64 is rotated to disconnect first torque amplifier 9 from second differential I0, simultaneously locking input gear 'H of second differential l0 by engaging diametral bar 68 into confronting notch 69. The correct change speed gears Il are then set in place. Computing mechanism 230 is set in place and synchronized with the machine in a manner identical with that described for cutting noncircular gears either manually or automatically.

SUMMARY From the foregoing it will be seen that we have provided a machine consisting of a standard gear shaper modified to permit a speed of rotation of the work table which may be continually varied in accordance with a predetermined pattern, and also allowing for a distance between the center of the cutter and the center of the work table which may be continually varied in accordance with a predetermined pattern; that We have provided a machine in which the continually varied speed of rotation of the work table and the continually varied distance between the center of the cutter and the center of the work table are controlled by mechanisms which operate at a large scale factor advantage, thus reducing the accuracy requirements of the controlling machine parts; that we have provided a machine which is capable of attaining the foregoing objects but which nevertheless is capable of use as a standard gear shaper for producing circular gears; and that our inventive machine is capable i6 of producing non-circular mechanical elements, such as gears or cams, in a simple, economical, and expeditious manner directly from the computed drafts.

To those generally familiar with the art it will be obvious that our invention can be .practiced with machines having somewhat different parts arrangements than that herein illustrated and described, without materially departing from the spirit and scope of our improvement. Our invention is therefore extensive in its adaption and is not to be restricted to the specific form here shown by way of illustration.

We claim:

1. A machine for shaping non-circular cams, gears, and the like, comprising: a motor; a table for supporting a work piece undergoing shaping; a rst power-transmitting linkage connecting said motor so as to rotate said table and including, a rst variable-speed device having an input member driven by said motor, an output member, and a first adjustable connecting member providing a driving connection between said members; a first controller moving said iirst connecting member so as to vary the output speed of said first linkage in accordance with the outline of the work piece undergoing shaping; a cutter for shaping the work piece; a second power-transmitting linkage connecting said motor to said cutter so as to cause relative movement between the center of the work piece and the center of the cutter and including, a second variable speed device having an input member driven by said motor, an output member, and a second adjustable connecting member providing a driving connection between said members; and a second controller moving said second connecting member so as to vary the output speed of said second linkage in accordance with the outline of the work piece undergoing shaping.

2. In a machine for cutting non-circular gears, cams, or the like, from a at blank, including a table on which the blank to be cut is mounted, a cutter for shaping the blank, and a motor for driving said table and said cutter, mechanism for varying the distance between the center of the blank being cut and the center of said cutter, said mechanism including, a lead screw'adapted to be locked against rotation, a tube enclosing a portion of said lead screw so as to be traversible therealong, a saddle mounted for translatory movement along said lead screw and containing mechanism for rotating and reciprocating said cutter, a nut comprising part of said tube and linked to said saddle while being threadedly mounted on said lead screw so as to be traversible therealong upon rotation of said tube, a gear so mounted on said tube that the gear is keyed against rotary movement relative to said tube but the tube is free for longitudinal movement relative to said gear, and power-transmitting mechanism connecting said motor to said-gear so that said gear together with the tube, nut, saddle and cutter linked thereto are driven at a selectively variable rate of speed, whereby the movement of the cutter relative to the blank may likewise be had at a selectively variable rate of speed.

3. In a machine for shaping non-circular cams, gears, and the like, a tool transmission comprising: a motor; a cutter for shaping a work piece; a power-transmitting linkage connecting said motor to said cutter so as to cause relative movement between the center of the cutter and the center of the work piece undergoing shaping and including, avariable speed device having'an input member drivenby said motor,.an outputmember, and anad'justable connectingmember providing a driving. connection betweentsaid members; and a .positioncontrolling mechanism for moving. said connecting member so as to vary'the output position of said linkage 'in accordance With the outline of the4 workpiece undergoing shaping, said mechanism including a drum driven by said motor and adapted to carry on it a curve representing a function `towhich it is desired to have correspond the amount of movement of said connecting member, and means mechanically linked with said cutter and said drum for controllably adjusting the amount of movement of the cutterrelative to the workpiece.

4. In a machine for shaping non-circular cams, gears, 'and the like, a Work table drive comprisving: amotor; a table for supporting a work piece undergoing' shaping; a power-transmitting linkage connecting said motor so as to rotate said table and including, a variable-speed device having an input member driven by said motor, an output member, and an adjustable connecting member providing a driving connection between said members; and a position controlling mechanism for varying the output position of said linkage in accordance with the outline of the work piece undergoing shaping, said mechanism including a drum driven by said motor and adapted to carry on it a curve representing the function to which it is desired to have correspond the amount of movement to said connecting member, and means mechanically linked with said table and said drum for controllably adiusting the amount of movement of the table relative to the workpiece.

5. In a machine for shaping non-circular cams, gears and the like, a tool transmission comprising: a motor; a cutter for shaping a work piece; a power-transmitting linkage connecting said motor to said cutter so as to cause relative movement between the center of the cutter and the center of the work piece undergoing shaping; and a position controlling mechanism for varying the output position of said linkage in accordance with the outline of the work piece undergoing shaping, said mechanism including a drum driven by said motor and adapted to carry on it a curve representing a function to which it is desired to have correspond the amount of movement of said linkage, and means mechanically linked with said cutter and said drum for controllablv adjusting the amount of movement of the cutter relative to the workpiece.

6. In a machine for shaping non-circular cams, gears, and the like, a work table drive comprising: a motor; a table for supporting a work piece undergoirn.y shaping: a power-transmitting linkage connecting said motor to said table so as rotatively to move said table; and a position controlling mechanism for varying the output position of said linkage in accordance with the outline ofthe work piece undergoing shaping, said mechanism including a drum driven by said motor and adapted to carry on it a curve representingv a function to which it is desired to have correspond the amount of movement oi' said linkage, and means mechanically linked with said table and said drum for controllably adjusting the amount of movement of the table relative to the workpiece.

'7. A Shaper adapted to cut flat machine parts to non-circular outline, comprising: a motor; a rst drum driven by said motor and adapted to carry on it a curve representing the..function to which it is desired to have correspond the speed of rotation of the part being cut; a rst reticle aligned with the curve on said drum so that an observer can note any variation from the output represented by said curve; a rst variable speed mechanism having a first driving member driven by said motor, a rst driven member, and a first intermediate member movable to vary the speed with which said first driving member drives said rst driven member; rst controlling means for adjusting the effective position of said first intermediate member; a feed-back connection from said rstdriven member to said first drum whereby any variation in the outputspeed of said first variable speed mechanism appears in the speed of movement of said 4first drum; a table, on which theA machine part being cut is mounted, driven by said first driven member; a second drum driven by said motor and adapted to carry on it a curve representing the function to which it is desired to have correspond the distance between the center of the machine part being cut and the center of said table; a second reticle aligned with the curve on said second drum so that an observer can note any variation from the output speed represented by said curve; a second variable speed mechanism having a second driving member driven by said motor, a second driven member, and a second intermediate member movable to vary the speed with which said second driving member drives said second driven member; second controlling means for adjusting the effective position of said second intermediate member; a second .feed-back connection from said second driven member to said second drum whereby any variation in the output speed of said second variable speed mechanism appears in the speed of movement of said second drum; a cutter for shaping the machine part being cut; and mechanism supporting said cutter and connected to said second driven member so as to be driven thereby to vary the distance from the center of the pitch circle being cut on said machine part and the center of said cutter.

8. A Shaper adapted to cut flat machine parts to non-circular outline, comprising: a motor; a rst drum driven by said motor and adapted to carry on it a curve representing the function to which it is desired to have correspond the speed of rotation of the part being cut; a first reticle aligned with the curve on said drum so that an observer can note any variation from the output represented by said curve; a table, driven by said motor, on which the machine part being cut is mounted; means associated with said table and said nrst drum whereby any variation in the speed of the table is observed and adjusted for in the speed of movement of said rst drum; a second drum driven by said motor and adapted to carry on it a curve representing the function to which it is desired to have correspond the distance between the center of the machine part being cut and the center of said table; a second reticle aligned with the curve on said second drum so that an observer can note any variation from the output speed represented by said curve; a cutter for shaping the machine part being cut; supporting mechanism for said cutter connected to said motor so as to be driven thereby to vary the distance from the center of the pitch circle being cut on said machine part and the center of said cutter; and means associated with said cutter supporting mechanism and said second drum whereby any variation in the speed of cutter 19 support is observed and adjusted for in the speed of movement of said second drum.

9. A shaper adapted to cut fiat machine parts to non-circular outline, comprising: a motor; a member driven by said motor for acting on the machine part to be cut; a drum driven by said motor and adapted to carry on it a curve representing the function to which it is desired to have correspond the amount of movement of said member; a reticle aligned with the curve on said drum 'so that an observer can note any variation from the output represented by said curve; and means mechanically linked with said member and said drum for controllably adjusting the amount of movement of said member relative to said machine part.

10. In a machine for cutting non-circular gears, cams, or the like, from a flat blank, including a table on which the blank to be cut is mounted..

a cutter for shaping the blank, and a motor for driving said table and said cutter, mechanism for varying the distance between the center of the blank being cut and the center ofsaid cutter, said mechanism including,` a lead screw adapted to be locked against rotation, a nut linked with said cutter and mounted on said lead screw so as to traverse therealong and to cause relative movement between said cutter and said blank by said v'traversing movement, a gear so mounted on said nut that the gear is keyed against rotary movement relative to said nut but the nut isfr'ee'for longitudinal movement relative to said gear, and power-transmitting mechanism connecting said motor to said gear so that said gear together with the nut and cutter linked thereto are driven at a selectively variable rate of speed, whereby the movement of the cutter relative to the blank may likewise be had at a selectively variable rate of speed.

JOHN G. TAPPERT.

WILLIAM SPERLING.

REFERENCES CITED The following references are of record inthe file of this patent:

UNITED STATES PATENTS n Number Name Date 1,177,503 Fellows Mar. 28, 1916 1,716,115 Clark et al June 4, 1929 1,933,798 Gebers Nov. 7, 1933 2,116,593 Bouvier et al. May 10, 1938 2,151,743 Chladek Mar. 28, 1939 2,226,677 Vikhman Dec. 31, 1940 2,271,598 Maurer Feb. 3, 1942 2,443,793 Lensky et al June 22, 1948 FOREIGN PATENTS Number Country Date 513,715 Germany Dec. 1, 1930 

